Need help finding low cost replacement lift springs 4-6"

[04sshd]

My Jimmy is at the shop getting a GM 8.5 3/4 ton front and GM 14 bolt FF rear, and they're telling me my leaf spring bushings are shot. They want 6 hours labor plus parts ($150) at well over $110 an hour to change them out.

I'm sure there's gotta be low cost lift spring options that are far cheaper than their $800 quote.

I currently have 4" front springs, and 4" blocks in the rear. I'd like to just buy two new front and rear leafs with bushings to save on cost if I can get them for cheaper than what they want to charge me. Everywhere I search is selling lift kits with front springs and blocks for $400-600, once change the options to rear lift leafs they go up to $1000. I don't need all of the stuff in the lift kit as I already have it (u bolts, dampeners, drop steering brackets, etc) I'd like to just find two low cost 4" or 6" lift leafs if I can save some money by going that route. Does anyone know of any places to source just the leafs economically?